The Syntax of Answers to Positive Polar Questions in Jordanian Arabic

Responses to a polar question have recently received much attention in the syntactic literature (e.g., Yaisomanag, 2012 on Thi; Wu, 2016 on Taiwanese, Servidio et al., 2018 on Italian; among others). However, the syntax of yes-no questions in Arabic has been undermined in the literature. The present study provides a syntactic analysis of answers to positive/neutral polar questions in Jordanian Arabic. Jordanian Arabic is particularly relevant here because its system allows for a variety of answer expressions. For example, an answer to a polar question could be in the form of a particle (a: ‘yes’ and laʔ ‘no’) or a finite verb echoing the verb of the question. Following Holmberg (2016), we demonstrate that these expressions are full sentences derived by ellipses. We assume that a yes-no question has an unvalued, free polarity variable [±Pol] that needs to be assigned a value. Deriving the answer would provide a value for this variable. This involves copying the TP of the question and merging an answer particle or an abstract polarity feature (affirmative or negative) in spec-Foc to value the unvalued feature of Pol; then the TP of the answer gets deleted at the PF component under identity with the TP of the question

Some Investigations on the role of microparticles on the low salinity process

Several papers dealing with laboratory experiments or field operations confirm that, in some circumstances, low salinity waterflooding improves oil recovery. However, the basic mechanisms explaining the oil recovery improvement are not clearly established. The literature points out several hypotheses, among them is the role of clay particles detachment and migration. Experiments using an intermediate-wet clayey sandstone were first performed showing an oil recovery increment when the injected brine salinity was reduced. SEM observations on native and flushed cores show the differences of pore surfaces before and after the low salinity waterflooding and the peculiar role of clay particles. Following this trail, in a second set of experiments we investigated the role of microparticles on the formation and stability of brine/oil emulsions when the salinity is changed. For that, we used calibrated latex particles negatively charged and several oils (mineral, crude and a blend of the two). Emulsion samples were observed using an optical microscope to determine their droplet size distributions and interface structures. The macroscopic stability of the emulsions was also investigated. The results show that the particle wettability, which is related to its surface charge and brine salinity, plays a central role. For high salinity the particles are hydrophobic and migrate toward the brine/oil interface forming a stable emulsion known as “Pickering emulsion”. For low salinity the particles are hydrophilic and the emulsion is not stable. In a third step the same latex particles were deposited in an artificial consolidated porous medium prior to two phase flow experiments. Our results show that even if no recovery improvement is observed, colloidal particles are recovered at the outlet when low salinity waterflooding is performed. The additional oil recovery during a low salinity brine injection is not a direct consequence of the particles mobilization but involves several mechanisms such as rock and brine composition, particle and oil nature, wettability, …. A thorough analysis of all these mechanisms calls upon further studies.Collaboration avec TOTA

Some Investigations on the role of microparticles on the low salinity process

Several papers dealing with laboratory experiments or field operations confirm that, in some circumstances, low salinity waterflooding improves oil recovery. However, the basic mechanisms explaining the oil recovery improvement are not clearly established. The literature points out several hypotheses, among them is the role of clay particles detachment and migration. Experiments using an intermediate-wet clayey sandstone were first performed showing an oil recovery increment when the injected brine salinity was reduced. SEM observations on native and flushed cores show the differences of pore surfaces before and after the low salinity waterflooding and the peculiar role of clay particles. Following this trail, in a second set of experiments we investigated the role of microparticles on the formation and stability of brine/oil emulsions when the salinity is changed. For that, we used calibrated latex particles negatively charged and several oils (mineral, crude and a blend of the two). Emulsion samples were observed using an optical microscope to determine their droplet size distributions and interface structures. The macroscopic stability of the emulsions was also investigated. The results show that the particle wettability, which is related to its surface charge and brine salinity, plays a central role. For high salinity the particles are hydrophobic and migrate toward the brine/oil interface forming a stable emulsion known as “Pickering emulsion”. For low salinity the particles are hydrophilic and the emulsion is not stable. In a third step the same latex particles were deposited in an artificial consolidated porous medium prior to two phase flow experiments. Our results show that even if no recovery improvement is observed, colloidal particles are recovered at the outlet when low salinity waterflooding is performed. The additional oil recovery during a low salinity brine injection is not a direct consequence of the particles mobilization but involves several mechanisms such as rock and brine composition, particle and oil nature, wettability, …. A thorough analysis of all these mechanisms calls upon further studies.Collaboration avec TOTA

Numerical Simulation of Yield Stress Fluid Flow in Capillary Bundles: Influence of the Form and the Axial Variation in the Cross Section

In this paper, we investigate possible improvements that can be made to the bundle of capillaries model in order to better represent the flow of yield stress fluids through porous media. This was examined by performing extensive and progressive numerical simulations and by introducing the non-circularity of channels’ cross section and/or its variability along the channels’ axis. It is shown that if only the non-circularity of channels’ cross section is taken into account, a moderate influence is observed on both critical pressure gradient for the flow onset and the flow rate/pressure gradient Q(∇P) relationship. However, the axial variation in capillaries’ cross section has proved to be more impacting the computed flow rate/pressure gradient data. We show hence that when available pore throat and pore body size distributions are used to construct the bundle of axially varying capillaries, the obtained Q(∇P) data do fit well experimental results corresponding to the flow of a Bingham-like fluid through a bed of randomly packed mono-sized spheres

Three-dimensional microscale simulation of colloidal particle transport and deposition in chemically heterogeneous capillary tubes

The effect of surface chemical heterogeneity and hydrodynamics on particle transport and deposition in porous media was investigated by microscale simulations using a colloidal particle tracking model, called 3D-PTPO (Three-dimensional particle tracking model by Python® and OpenFOAM®) code. This work is aimed as a step toward modeling of transport and deposition in porous media idealized as a bundle of straight capillary tubes. Therefore, our focus is put upon a three-dimensional capillary with periodically repeating chemically heterogeneous surfaces namely crosswise strips patterned and chess board patterned. The main feature of this recent model is to renew the flow field by reconstructing the pore structure, to take the pore surface modification induced by the volume of the deposited particles into account. The dependency of the deposition probability and the dimensionless surface coverage (Γ/ΓRSA) on the frequency of the pitches (λ), the Péclet number (Pe) and the favorable area fraction (θ), as well as the distribution of the spatial density of deposited particles along the capillary tube were studied. The results indicate that particles tend to deposit at the leading and trailing edges of the favorable strips, and the deposition is more uniform along the patterned capillary compared to the homogeneous one. In addition, for the chemically heterogeneous capillary, in a similar manner as for the homogeneous one, a definite plateau exists for the Γ/ΓRSA at low Péclet values. For high Pe values, the declining trend for Γ/ΓRSA versus Pe is in good agreement with the derived power law dependence already observed in the literature for fully adsorbing surfaces. Moreover, for fixed θ the deposition probability is linearly correlated with λ and for given λ, such a deposition probability is also a linear function of θ

Three-dimensional microscale simulation of colloidal particle transport and deposition in model porous media with converging/diverging geometries

The microscale simulation of colloidal particle transport and deposition in porous media was achieved with a novel colloidal particle tracking model, called 3D-PTPO (Three-Dimensional Particle Tracking model by Python® and OpenFOAM®), using a Lagrangian method. Simulations were performed by considering the elementary pore structure as a capillary tube with converging/diverging geometries (tapered pipe and venturi tube). The particles are considered as a mass point during transport in the flow and their volume is reconstructed when they are deposited. The main feature of this novel model is to renew the flow field by reconstructing the pore structure by taking the volume of the deposited particles into account. The influence of the particle Péclet number (Pe) and the pore shape on the particle deposition therein is investigated. The results are analyzed in terms of deposition probability and dimensionless surface coverage as a function of the number of injected particles for a vast range of Péclet numbers thus allowing distinguishing the behavior in diffusion dominant and advection dominant regimes. Finally, the maximum dimensionless surface coverage Γfinal/ΓRSA is studied as a function of Pe. The declining trend observed for high Pe is in good agreement with experimental and simulation results found in the literature

Mise en évidence du facteur de retard dans la cinétique de dépôt colloïdal en milieux poreux

Les milieux poreux naturels, comme les sols ou les aquifères, contiennent des particules colloïdales naturelles dont le diamètre est inférieur au micron. Selon des conditions hydrodynamiques et géochimiques, celles-ci peuvent être transportées par l'eau, développer une forte réactivité et une mobilité importante et agir comme des vecteurs d'éventuelles substances polluantes fixées à leur surface. Certaines particules colloïdales comme les bactéries sont également susceptibles de présenter, en elles-mêmes, un risque pour l'environnement et la santé. Le transport colloïdal peut donc contribuer à la dissémination rapide de polluants dans les sols et les eaux souterraines. Toutefois, le processus d'adsorption (dépôt sur la roche) peut limiter fortement la mobilité des colloïdes dans les milieux poreux

Numerical Investigation to Quantify the Rate of Damage within Mortar Bituminous Materials: Modeling of Cracks Initiation and Propagation

Asphalt concrete is highly used to construct pavement layers in the civil engineering field. It is defined as a complex medium composed of aggregates (inclusions), mortar (matrix) and air void. The mortar itself is a mixture of fillers, sand and bitumen. Furthermore, mortar is the phase that links the coarse aggregates. In general, fracture of asphalt concrete occurs within mortar or among aggregate-mortar interface. Therefore, two types of fracture can be identified, i.e., adhesive and cohesive damages. The first type is occurred among the interface of aggregate-mortar. The second is taken place within the mortar. This paper presents numerical investigations of the damage initiation and stiffness degradation within the asphalt concrete matrix. Numerical simulations were carried out to investigate, firstly, how damage is initiated and developed, and then, to simulate how cracks can be initiated and propagated within this material. Cohesive finite elements method was adopted to simulate fracture. For adhesive damage, the model was represented by one rectangular aggregate that is linked to the asphalt concrete thanks to a thin layer of the mortar. For cohesive damage, the model was considered as a thick layer of the mortar in between two coarse aggregates. The applied loading was derived from the speed of traffic vehicle. A comparative analysis between four mortars was conducted. The effect of loading and the type of mortar on damage initiation and stiffness degradation will be shown. Moreover, the initiation and propagation of cracks as function of loading and stiffness modulus will be illustrated

Flow of yied stress fluids through porous media : simulations, experiments and applications

A Yield Stress fluids injection porosimetry Method (YSM) has recently been developed as a simple potential alternative to the extensively used Mercury Intrusion Porosimetry (MIP). Its main advantage is the use of a nontoxic fluid instead of mercury used in MIP. Using this method, the Pore Size Distribution (PSD) of a porous medium is obtained by measuring the flow rate / pressure gradient relationship obtained by injecting a yield stress fluid in the porous medium. The principle of the method and some experimental results obtained using this technique will be presented and will be compared to those obtained by Mercury Intrusion Porosimetry (MIP). In the Yield Stress fluid injection porosimetry method, the main assumption is that the porous medium is described as a bundle of straight capillaries of circular cross-section following a given pore size distribution. This simple model is revisited by introducing both non-circular and axially varying cross-sections. Two key points are tackled using numerical simulations: the flow onset at minimal pressure drop and the variation of the flow rate vs the pressure gradient. These results are finally used to show that the flow rate / pressure gradient relationship of a yield stress fluid through a porous medium can be more closely predicted using a bundle of capillaries of irregular cross-sections rather than using the classical bundle of straight circular capillaries